Helical insertion infusion device

ABSTRACT

A system for delivering fluid to a user transcutaneously includes a subcutaneous infusion cannula base assembly, a cannula inserter assembly and a fluid connection assembly. The subcutaneous infusion cannula base assembly is configured to be located on the user&#39;s skin. The cannula inserter assembly is coupled to the cannula base assembly and is configured to drive an infusion cannula through the user&#39;s skin in a nominally helical trajectory. The fluid connection assembly is configured to fluidically connect the cannula base assembly to a source of delivery fluid. Cannula and stylet assemblies configured for helical or non-helical insertion are also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/943,517, filed Apr. 2, 2018 and titled “HELICAL INSERTION INFUSIONDEVICE,” which claims the benefit of U.S. Provisional Patent ApplicationNo. 62/480,190, filed Mar. 31, 2017 and titled “SPIRAL INSERTIONINFUSION DEVICE,” and U.S. Provisional Patent Application No.62/517,825, filed Jun. 9, 2017 and titled “SPIRAL INSERTION DEVICE,”each of which is here incorporated by reference in its entirety.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

FIELD

Described herein are devices for delivering therapeutic fluids, and moreparticularly small, disposable, portable infusion devices and methodsthat can be used to transcutaneously deliver fluids safely and simply toa patient.

BACKGROUND

During drug delivery, it is often desirable to bypass the digestivesystem of a patient to avoid degradation of the drug's activeingredients that can be caused by the catalytic enzymes in the digestivetract and liver. Delivery of a drug other than by way of the intestinesis known as parenteral delivery. Parenteral delivery of drugs in liquidform is often desired to enhance the effect of the substance beingdelivered, insuring that the unaltered medicine reaches its intendedsite at a significant concentration. Moreover, undesired side effectsassociated with other routes of delivery, such as systemic toxicity, canpotentially be avoided by parenteral delivery. Further, many medicinesare only available in liquid form, and/or the liquid may have desirablecharacteristics that cannot be achieved with solid or pill form.Delivery of liquid medicines may best be accomplished by infusingdirectly into the cardiovascular system via veins or arteries, into thesubcutaneous tissue, or directly into organs, tumors, cavities, bones,or other site-specific locations within the body.

Parenteral delivery of liquid medicines into the body is oftenaccomplished by administering bolus injections using a needle andreservoir or continuously by gravity driven dispensers or transdermalpatch technologies. Bolus injections often imperfectly match theclinical needs of the patient and usually require larger individualdoses than are desired at the specific time they are given. Continuousdelivery of medicine through gravity feed systems compromise thepatient's mobility and lifestyle and limit the therapy to simplisticflow rates and profiles. Transdermal patches have special requirementsof the medicine being delivered, particularly as it relates to themolecular structure, and similar to gravity feed systems, the control ofthe drug administration is severely limited.

Ambulatory infusion pumps have been developed for delivering liquidmedicaments to a patient. These infusion devices have the ability tooffer sophisticated fluid delivery profiles that can provide bolusdelivery, continuous infusion, and variable flow rate delivery.Ambulatory infusion pumps, however, can be problematic, as the user isgenerally forced to choose between a soft delivery cannula, which tendsto have high initial failure rates and is prone to kinking, or a steelneedle set, which has a lower initial failure rate but is associatedwith increased pain and shortened time of use. Additionally, thechallenge with current infusion sets is that the 90-degree (i.e., rigidcannula) infusion sets, which are easiest to insert, are also associatedwith the highest rates of failure, partially due to needle breakageand/or fluid leaking out of the relatively short insertion path.Further, infusion sets with a soft cannula, however, tend to be harderto insert and/or are associated with increasedapprehension/intimidation.

Moreover, a necessary and important step in preparing an infusion setfor use is filling the tubing with liquid medicament, such as insulin tobe delivered to a person with diabetes. This is often done by attachingthe infusion set tubing to either the insulin pump reservoir or theinsulin pump reservoir adaptor (e.g., a device that holds the reservoirinto the pump). The pump is then programmed to fill the tubing withinsulin. This is not an automatic process. The user is typically eitherasked to hold down a button until the tubing is filled or to program anamount believed to be sufficient to fill the tubing. The user isinstructed not to move on to another step until they observe insulindrops exiting the distal end of the tubing to infusion site connectionor the distal end of the infusion cannula. The observation confirms thatthe tubing has been filled.

Tube filling carries two risk cases. The first risk case is when theuser attempts to fill the tube and makes the mistake of connecting thetube to an infusion set that has already been inserted into their body.This would prevent the user from knowing when the tube had beencompletely filled and would result in any excess insulin delivered in anattempt to fill the tube to be delivered to the pump user, resulting inan over delivery. Over delivery carries with it a significant risk ofhypoglycemia (low blood glucose levels). The second risk case isincomplete filling of the tubing. Failure to completely fill the tubingcan lead to under delivery of insulin. This in turn can lead tohyperglycemia (elevated glucose levels). The amount of missed insulin(10 to 15 units) can be approximately 25 to 50% of a typical pump user'sdaily dose (˜42 units) but could exceed the total daily dose of a pumpuser with higher than typical insulin sensitivity. In many cases, themissed insulin associated with a non-filled or partially filled tubecauses a significant health risk to the pump user. Filling the tubing isnot an easy task, especially for those with any macular degeneration, asis often associated with diabetes progression.

Accordingly, an ambulatory infusion pump set that is efficient, safe,effective, easy to insert into a patient, and easy/safe to fill isdesired.

SUMMARY OF THE DISCLOSURE

In general in one embodiment, a device for delivering fluid to a patientincludes a housing assembly, a subcutaneous infusion cannula assemblyextending from the housing, an insertion mechanism, and a fluidconnection port. The insertion mechanism is configured to extend theinfusion cannula in a helical path from the housing assembly. The fluidconnection port is configured to connect the device to a source ofdelivery fluid.

This and other embodiments can include one or more of the followingfeatures. The infusion cannula can have a pre-set curved shape. Thedevice can further include a sharp inner stylet configured to extendthrough the infusion cannula. The sharp inner stylet can have a pre-setcurved shape. The insertion mechanism can further include mechanicalfeatures to define or limit the depth of extension of the infusioncannula from the housing assembly. The insertion mechanism can furtherinclude a rotational drive mechanism configured to rotate the infusioncannula as the cannula is extended from the housing assembly. Therotational drive mechanism can be a spring. The housing can include anadhesive on at least one surface thereof configured to attach the deviceto skin of the patient. The subcutaneous infusion cannula can beflexible. The cannula can include an outer tube and an innerreinforcement coil. The cannula can include two or more fluid exit holesat or near the distal end thereof. The insertion mechanism can includean automatic retraction mechanism for moving the stylet from theadvanced position to the retracted position on completion of theinsertion cycle. The housing assembly can contain a releasable fluidinterconnect assembly to connect the subcutaneous cannula assembly tothe source of fluid.

In some embodiments, a system for delivering fluid to a usertranscutaneously includes a subcutaneous infusion cannula base assembly,a cannula inserter assembly and a fluid connection assembly. Thesubcutaneous infusion cannula base assembly is configured to be locatedon the user's skin. The cannula inserter assembly is coupled to thecannula base assembly and is configured to drive an infusion cannulathrough the user's skin in a nominally helical trajectory. The fluidconnection assembly is configured to fluidically connect the cannulabase assembly to a source of delivery fluid.

In some of the above embodiments, the inserter assembly is removablycoupled to the cannula base assembly. The system may further comprise asharp inner stylet configured to extend through the infusion cannula.The sharp inner stylet may have a pre-set curved shape. In someembodiments, the cannula base assembly includes an adhesive on at leastone surface thereof configured to attach the cannula base assembly tothe user's skin. In some embodiments, the subcutaneous infusion cannulais flexible. The cannula may include an outer tube and an innerreinforcement coil. In some embodiments, the cannula includes two ormore fluid exit holes at or near the distal end thereof.

In some embodiments, the inserter assembly includes an automaticretraction mechanism configured to move the stylet from an advancedposition to a retracted position after completion of a cannula insertioncycle. The inserter assembly may also include an automatic releasemechanism configured to decouple the inserter assembly from the cannulabase assembly after completion of a stylet retraction cycle. Theinserter assembly may be configured to automatically perform the cannulainsertion cycle, the stylet retraction cycle and a release cycle insuccession after a single trigger event without further interaction fromthe user. In some embodiments, the inserter assembly includes a singledrive spring configured to supply all energy required to drive thecannula insertion cycle, the stylet retraction cycle and the releasecycle. The system may further comprise packaging for enclosing at leastthe inserter assembly before use. The inserter assembly may include atleast one drive spring, and the inserter assembly may be configured toautomatically charge the drive spring as the packaging is being opened.

In some embodiments, the fluid connection assembly of the infusionsystem includes tubing and an element or assembly that changes colorwhen the tubing has been primed with fluid. The fluid connectionassembly may include a releasable fluid interconnect assembly configuredto releasably connect the cannula base assembly to the source ofdelivery fluid, and the source of delivery fluid may be external to thecannula base assembly. The releasable fluid interconnect assembly mayinclude a needle and a septum, and the fluid interconnect assembly maybe configured to insert an end of the needle through the septum after acannula stylet is withdrawn from the septum.

In some embodiments, a system for delivering fluid to a usertranscutaneously includes a subcutaneous infusion cannula base assembly,a cannula inserter assembly and a fluid connection assembly. The cannulabase assembly is configured to be located on the user's skin andincludes an infusion cannula having a central lumen therethrough. Thecannula includes a reinforcing coil extending along a portion of thecentral lumen. The coil has at least two different pitches along itslength. The cannula inserter assembly is coupled to the cannula baseassembly and includes a sharp stylet configured to pass through thecentral lumen of the cannula. The inserter assembly is configured todrive the stylet and infusion cannula together through the user's skinwithout a needle placed over the cannula. The fluid connection assemblyis configured to fluidically connect the cannula base assembly to asource of delivery fluid.

In some of the above embodiments, the reinforcing coil has a firstsection with a first coil pitch and a second section with a second coilpitch, the first section being located more distally in the cannula thanthe second section. In these embodiments, the first coil pitch isgreater than the second coil pitch. In some embodiments, the first coilpitch is an open pitch and the second coil pitch is a closed pitch. Insome embodiments, the first section includes a plurality of holes thougha side wall of the cannula. The inserter assembly may be configured todrive the stylet and infusion cannula together through the user's skinat a 90 degree angle. The inserter assembly may be configured to drivethe stylet and infusion cannula together through the user's skin at anangle of less than 45 degrees.

In some embodiments, a system for delivering fluid to a usertranscutaneously includes a subcutaneous infusion cannula base assembly,a cannula inserter assembly and a fluid connection assembly. The cannulabase assembly is configured to be located on the user's skin andincludes an infusion cannula formed from a polyether block amidethermoplastic elastomer having a central lumen therethrough. The cannulahas a nominal outside diameter no greater than 0.56 mm. The cannulaincludes a reinforcing coil extending along a portion of the centrallumen. The reinforcing coil has a nominal inside diameter and a nominaloutside diameter. The nominal outside diameter is the same as a nominalinside diameter of the central lumen it resides in. The reinforcing coilhas a first section with a first coil pitch and a second section with asecond coil pitch. The first coil section is located more distally inthe cannula than the second section. The first coil pitch is an openpitch and the second coil pitch is a closed pitch. The first sectionincludes a plurality of holes though a side wall of the cannula. Thecannula includes a distalmost section having an outer taper of between10 and 30 degrees and no reinforcing coil located in the distalmostsection. A portion of the cannula is siliconized to reduce insertionforce. The cannula inserter assembly is coupled to the cannula baseassembly and includes a sharp stylet configured to pass through thecentral lumen of the cannula. The stylet has a nominal outside diameterthat is the same as the nominal inside diameter of the reinforcing coil.The stylet has a sharpened distal tip that extends from the distalmostsection of the cannula. The inserter assembly is configured to drive thestylet and cannula together through the user's skin without a needleplaced over the cannula. The fluid connection assembly is configured tofluidically connect the cannula base assembly to a source of deliveryfluid.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the disclosure are set forth with particularity inthe claims that follow. A better understanding of the features andadvantages of the present disclosure will be obtained by reference tothe following detailed description that sets forth illustrativeembodiments, in which the principles of the disclosure are utilized, andthe accompanying drawings of which:

FIG. 1A shows an exemplary infusion device.

FIG. 1B shows an exemplary cannula for use with the infusion device ofFIG. 1A.

FIG. 2A shows the bottom surface of another exemplary infusion device.

FIG. 2B shows a cannula release mechanism that can be positioned withinthe infusion device of FIG. 2A.

FIG. 3A shows another exemplary infusion device.

FIG. 3B shows a cannula release mechanism of the infusion device of FIG.3A.

FIG. 3C is a cross section of the infusion device of FIG. 3A.

FIG. 3D shows the top of an infusion device of FIG. 3A.

FIG. 3E is a cross section of the infusion device of FIG. 3A.

FIG. 3F shows the top of the infusion device of FIG. 3A with the coverremoved.

FIG. 4A shows an exemplary external insertion device.

FIG. 4B is an exploded view of the external insertion device of FIG. 4A.

FIG. 4C is a cross section of the external insertion device of FIG. 4A.

FIG. 5A shows an external insertion device mated with an infusiondevice.

FIGS. 5B and 5C are cross-sections of FIG. 5A taken along a verticalplane.

FIGS. 5D and 5E are cross-sections of FIG. 5A taken along a horizontalplane.

FIGS. 6A-6D show an exemplary cannula for use with the infusion devicesdescribed herein.

FIG. 7A shows a cannula with a stylet extending therethrough.

FIG. 7B shows the stylet retracted.

FIG. 8 shows an exemplary distal tip of a cannula.

FIGS. 9A-9C show an infusion device and an external inserter combined ina single packaging element.

FIGS. 10A-10E show another exemplary infusion device.

FIG. 11 is a perspective view showing the outer packaging for anexemplary transcutaneous infusion system.

FIG. 12 is an exploded view showing the infusion system of FIG. 11 withthe packaging opened and the inserter assembly removed.

FIG. 13 is an exploded top view showing the components of the infusionsystem of FIG. 11 without the inserter assembly.

FIG. 14 is an exploded bottom view showing the components of theinfusion system of FIG. 11 without the inserter assembly.

FIG. 15 is a top view showing the inside of the packaging jar of theinfusion system of FIG. 11.

FIG. 16 is a bottom view showing the inside of the packaging lid of theinfusion system of FIG. 11.

FIG. 17 is a top perspective view showing the inserter assembly of theinfusion system of FIG. 11.

FIG. 18 is a bottom perspective view showing the inserter assembly ofthe infusion system of FIG. 11.

FIG. 19 is a side view showing the inserter assembly of the infusionsystem of FIG. 11.

FIG. 20 is a top exploded view showing the components of the inserterassembly of the infusion system of FIG. 11.

FIG. 21 is a bottom exploded view showing the components of the inserterassembly of the infusion system of FIG. 11.

FIG. 22 is a cross-sectional view taken through the release buttons ofthe inserter assembly of the infusion system of FIG. 11.

FIG. 23 is a cross-sectional view taken between the release buttons ofthe inserter assembly of the infusion system of FIG. 11.

FIGS. 24A-24P are a series of views of the base assembly of the infusionsystem of FIG. 11 showing a sequence of events starting with the baseassembly first being attached to the user's skin and through use of theinfusion system.

FIG. 25A is a fragmentary top view in partial cross-section showing thecannula of the infusion system of FIG. 11.

FIG. 25B is a fragmentary side view of the cannula shown in FIG. 25A.

FIG. 25C is an enlarged view of the distal tip of the cannula shown inFIG. 25A.

FIG. 26A is a top plan view showing the stylet of the infusion system ofFIG. 11.

FIG. 26B is a fragmentary side view showing the distal and proximal endsof the stylet shown in FIG. 26A.

FIG. 26C is a fragmentary side view showing the distal and proximal endsof the cannula shown in FIGS. 25A-25C assembled with the stylet shown inFIGS. 26A and 26B.

FIGS. 27A and 27B are graphs showing results of lateral stiffness testsperformed on the cannula of FIGS. 25A-25C and the cannula and styletassembly of FIG. 26C, respectively.

FIGS. 28A and 28B are graphs showing results of insertion force testsperformed on the cannula and stylet assembly of FIG. 26C.

FIG. 29A is a bottom view showing the base assembly of the infusionsystem of FIG. 11.

FIG. 29B is a table and diagram showing the trigonometric relationshipsbetween parameters of the cannula of the infusion system of FIG. 11.

DETAILED DESCRIPTION

Described herein are subcutaneous infusion devices that promotewearability, increase wear-life, and effectively deliver fluidtranscutaneously. The in-dwelling infusion devices may include amulti-orifice soft cannula and a user-depth controlled curved insertioncannula that provides for a spiral or helical insertion path through thetissue.

As shown in FIGS. 1A and 1B, an exemplary infusion device 100 includes ahousing assembly 101, a hollow curved cannula 102, and a driver to whichthe hollow curved cannula 102 is attached. The driver rotates the hollowcurved cannula 102 and simultaneously translates the hollow curvedcannula 102 into the soft tissue. The device 100 is configured to insertthe curved cannula 102 spirally or helically into soft tissue, therebybetter fixing the cannula 102 in the soft tissue. In some embodiments,the infusion device 100 can be configured to interface with an infusionpump.

In some embodiments, the hollow curved cannula 102 can be a 24 Gacatheter (0.56 m outer diameter) made of a polymer-coated stainlesssteel coil. In other embodiments, the cannula 102 can be made entirelyof metal, e.g., stainless steel. The curved shape can, for example, beheat set into the cannula 102. The curved shape of the cannula 102 can,for example, have a radius of curvature of between 0.5 inches and 1.25inches. Further, the curved shape of the cannula 102 can have a pitch,for example, of between 10 mm and 30 mm. In some embodiments, thecannula 102 can end in a sharpened tip. The hollow curved cannula 102can further include a series of perforations, including one or morefluid exit holes 111 along the length thereof in a variety of patterns.Further, the hollow curved cannula 102, due to its curvature, can beinserted at a 30°-60° angle relative to the plane of the skin surface ina spiral or helical path that accommodates target insertion depthsranging from 6 to 10 mm. Further, in some embodiments, the curve of thehollow curved cannula can provide for a 1-3 cm diameter insertion path.

A similar infusion device 200 is shown in FIGS. 2A-2B. The infusiondevice 200 includes a housing 201. The underside 221 of the housing canbe flexible and include an adhesive thereon for attachment to the skin.A release mechanism 210 can be positioned inside the housing 201 (FIG.2B shows the housing removed for clarity). Further, the releasemechanism 210 can include an rotatable disk 222 and an inner disk 224that are rotatable with respect to one another. The cannula 202 canextend from the outer disk 222 and can be wound or curled up within theinner radius of the outer disk 222. The inner disk 224 can be fixedrelative to the housing 201. A coiled or torsion spring 229 can bepositioned within the release mechanism 210 and attached to both theinner disk 224 and the outer disk 222. Further, the spring 229 can beheld in a loaded position when the cannula 202 is wound and positionedwithin the housing 201. Upon release of the spring 229 (e.g., by auser-activated button), the outer disk 222 can rotate relative to theinner disk 224, thereby causing the cannula 202 to rotate relative tothe housing 201. As the cannula 202 rotates, it can extend from anaperture 211 on the bottom surface 221 of the housing 201, therebyallowing the sharp tip of the cannula 202 to pierce the skin and extendin a spiral or helical path through the subcutaneous tissue. A secondcoiled spring 218 within the release mechanism 210 can be loaded so asto rotate the outer disk 222 in the opposite direction relative to theinner disk 224 when released (e.g., by a user-activated button), therebypermitting the cannula 202 to be retracted into the housing 201 by theuser as desired.

Another similar infusion device 300 is shown in FIGS. 3A-3E. In contrastto infusion device 200, however, device 300 is intended to be used witha separate external insertion device. The infusion device 300 includes ahousing 301 configured to house a release mechanism 310 and a curvedcannula 302. Similar to the release mechanism 210, release mechanism 310can include two disks 324, 322 that are rotatable relative to oneanother to allow the curved cannula 302 (fixed relative to the outerdisk 322) to rotate and extend through the aperture 311 on the bottomsurface 321 of the housing 301. This rotation can be activated, forexample, through an external device such as that shown and describedwith respect to FIGS. 4A-4C. Further, the release mechanism 310 caninclude a second spring (see FIG. 3F) configured to retract the cannula302 when released. The underside 321 of the housing 301 can be flexibleand include an adhesive thereon for attachment to the skin. As shown inFIG. 3C, a fluid inlet 397 can provide delivery fluid to the needle 302(e.g., through a detachable fluid connection 323). The fluid inlet 397can be fixed to the stationary inner disk 324, thereby maintaining afixed position relative to the fluid reservoir.

As shown in FIGS. 4A-4C, an insertion device 433 can be configured to beused with the infusion devices (such as device 300) described herein.The insertion device 433 can separately house the torsion spring 429 anda rotatable portion 454. Buttons 439 a,b can allow the user to releasethe spring 429 to provide rotation of the rotatable portion 454.Further, the insertion device 433 can include a user-adjustable knob 435configured to allow the user to set the depth of insertion (e.g., at 6,8, or 10 mm). The insertion device 433 can include features configuredto positively engage with the infusion device. For example, legs 441(see FIG. 4C) of the insertion device 433 can be configured to sitwithin indents 336 (see FIGS. 3B and 3D) on the cover 391 of the releasemechanism 310.

Use of the insertion device 433 with the infusion device 300 isdescribed with respect to FIGS. 5A-5E. To begin, the infusion device 300is adhered to the skin. The inserter 433 can then be coupled with thedevice 300 such that the legs 441 of the insertion device 433 extendwithin the indents 336 of the device 300. To release the cannula 302from the device 300 for insertion into the skin, the buttons 439 a,b(two are included for redundancy, but only one may be used) can bepushed downwards. Pushing the buttons 439 a,b downwards pushes on thecompression springs 449 a,b associated with the buttons 439 a,b, whichcauses the internal fixation element(s) 459 (see FIG. 5B) to releasefrom the rotatable portion 454. The torsion spring 429 will thenrelease, causing the rotatable portion 454 to rotate, and thus the outerdisk 322 of the insertion device 300 (and attached cannula 302) torotate. Such rotation of the cannula 302 results in unwinding thecannula 302 and inserting the cannula 302 into the skin in aspiral/helical manner (consistent with the curvature of the cannula302). Pushing of the buttons 439 a,b downwards can also advantageouslyhelp adhere the device 300 to the patient's skin during insertion of thecannula 302.

In some embodiments, the user can preselect the insertion depth usingthe knob 435 prior to inserting the cannula 302. As shown in FIGS.5D-5E, as the knob 435 is rotated to the desired position, extensions462 on the internal radius thereof engage with mating teeth 464 on aninternal fixed portion of the device 433. Doing so establishes theposition of a stop 455 (that rotates with knob 435). As such, when therotatable portion 454 rotates, it will be allowed to rotate only untilthe mating stop 457 hits the stop 455, thereby controlling the length ofthe cannula 302 that is released, and thus controlling the depth ofinsertion.

In some embodiments, to remove the cannula 302 from the patient, thecannula 302 can be retracted back into the body 301. For example, asshown in FIG. 3E, the infusion device 300 can include two tabs 348 a,b.When the tabs 348 a is pushed inwardly, the hook 346 (which is usuallyengaged with teeth 342 on the outer surface of the outer disk 322) canmove inwards to release from the teeth 342 (see FIG. 3B). When thisoccurs, the loaded spring 318 can release. The spring 318, in turn,which is connected to the inner and outer disks 324, 322, can then causethe outer disk 322 to rotate, pulling the cannula 302 back into the body301. In such an embodiment, the second spring 318 (see FIG. 3F) can becoiled or loaded in an opposite direction as the spring used forinsertion (e.g., spring 429), thereby permitting rotation of the disk322 and cannula 302 in the opposite direction. In some embodiments, bothtabs 348 a,b must be pushed simultaneously to activate the retractionmechanism, thereby preventing accidental retraction.

Another infusion device 1000 that is similar to infusion device 300 isshown in FIGS. 10A-10E. Similar to infusion device 300, however, device1000 is intended to be used with a separate external insertion device.The infusion device 1000 includes a rotational body 1010 configured torotate to extend cannula 1002 spirally or helically into the tissue, asdescribed above. The infusion device 1000 further includes a fixed baseplate 1024. The fixed base plate 1024 is attached to an adhesive layer1021 for adhering the device 1000 to the skin. As shown best in FIGS.10D and 10E, the fixed base plate 1024 includes a cannula guidance andsupport feature 1072 (e.g., a curved cut-out) therein, a detent lockfeature 1073, and a central post 1075 that acts as a rotational axis forthe rotational body 1010 and as a lumen for the passage of fluid to thecannula 1002. The detent lock feature 1073 is configured to engage whenthe rotational body 1010 reaches its full rotational travel distance.The fixed base plate 1024 advantageously provides rigidity to theadhesive layer 1021, cannula guidance during the insertion operation,attachment for the rotational body 1010, and cannula support duringnormal operation. Further, in some embodiments, the fixed base plate1024 can include a region of alternating color and/or alpha-numericcharacters that are only visible through a rotational body window atspecific angular sectors indicating a binary state (e.g.,ready/deployed/etc.).

A package 980 holding a combined insertion device 933 and infusion set900 is shown in FIGS. 9A-9C. The insertion device 933 is similar toinsertion device 433, and the infusion set 900 is similar to infusionset 1000. A packaging element 999 is used to surround the insertiondevice 933 and infusion set 900. The packaging 999 further includes aremovable cap 998.

The exterior packaging 999 of the insertion device 933 advantageouslyfacilitates or promotes a specific user operational sequence thatencourage proper use of the product and help ensure patient safety. Thatis, the insertion device 933 is packaged so as to encourage the tubingof the infusion device to be filled with fluid before inserting the set.As shown in FIGS. 9A-9B, the insertion device 933 thus includes externalpackaging 999 such that the tubing is presented to the user first (afterremoval of the cap 998) and the infusion set base and cannula are“behind” the tubing in the packaging 999 (i.e. can only be accessed oncethe tubing has been removed from the packaging 999).

The connection for tube to the pump is in an easy to reach location thatpresents itself to the use upon opening the packaging 999, therebyadvantageously encouraging the user to grab it first when unpacking theset. Further, the tubing-to-pump connection and the portion of thetubing immediately attached to it can be positioned/held within theexternal packaging 999 so that the tubing to pump connection can beremoved from the packaging 999 without removing the bulk of the tubing(i.e., the first foot or so of tubing comes lose with the tubing to pumpconnection but the rest of the tubing stays in place until intentionallyremoved). This allows the user to fill the tube without removing thebulk of it from the packaging 999 and without exposing the rest of theinfusion device 900 until after the tubing is filled. In concert withpositioning the pump connection at an easily accessible location, thetube-to-infusion set hub connection can be positioned in a lessaccessible location. This discourages the user from grabbing that endfirst and helps ensure the flow of fill tubing before inserting theinfusion set.

In some embodiments, the packing 999 can further include a materialthereon that changes color when droplets of insulin or diluent contactit. This advantageously helps the user know that the tubing has beenfilled. In some embodiments, the color changing material can be locatedso that when the package is resting on a flat surface, gravity directsany droplets exiting the distal end of the tubing towards the material.In an alternative embodiment, the distal portion of the tube to infusionset hub connector can contain the material that changes color when incontact with insulin or diluent.

Close-ups of an exemplary curved cannula 602 for use with any of theinfusion devices described herein are shown in FIGS. 6A-6D. The curvedcannula 602 can include a hollow tube 614 made of a with a softbio-compatible material. A spiraled or helical coil 644 can extendwithin the tube 614 to provide reinforcement thereto. In someembodiments, the tube 614 can be made of a plastic material such asTeflon or Nylon. In some embodiments, the coil 644 can be made of aplastic having a higher stiffness than the material of the tube 614 orcan be made of a metal. In some embodiments, the tube 614 is made ofmetal. In some embodiments, the coil pitch can be equal to or greaterthan the wire diameter. In some embodiments, an extruded reinforcementcan be used in place of the coil 644. The curved cannula 602 can furtherinclude a plurality of exit holes 611 at or near the distal end thereof.The holes 611 can be of a defined pattern, size, and shape (e.g.,circular or elongated slots). In some embodiments, the holes 611 canvary in diameter by linear distance from the distal end of the cannula.

Referring to FIGS. 7A and 7B, in some embodiments, a solid and pointedstylet 766 can be extended coaxially through the hollow cannula 702(including outer tube 714 and coil 744) and retracted during fluiddelivery. The solid wire stylet 766 can advantageously be used to piercethe derma during use. Further, in some embodiments, the stylet 766 canhave the curved shape that allows for spiral or helical insertion of thecannula 702 rather than the cannula 702 itself having the curved shape.In such an embodiment, the cannula 702 can be flexible so as to take thecurved shape of the stylet 766. In some embodiments, the stylet 766 canhave a sharpened distal tip that is a single bevel, has multiple bevelfacets, that has a pencil-type tip, and/or a conical tip. Where astylet, such as stylet 766, is used, the retraction mechanism describedabove (e.g., using a second user-activated spring), can be used only toremove the stylet, leaving the outer tube in place.

In some embodiments, the cannula can be replaced with a spirally orhelically inserted body analyte sensor. For example, the body analytesensor can be a wire assembly including chemistry components.

Further, in some embodiments, the cannula, once inserted in a spiral orhelical fashion, can function as a spring member to providethree-dimensional strain relief. Thus, for example, the infusion setadhesively attached to the dermis can freely move without transferringmoment energy to the cannula.

In some embodiments, the cannula is soft and semi-rigid and is coatedwith a lubricating element, such as a liquid, a conformal coatingapplied by dipping and drying, or a coating applied by gas or vapordeposition.

In some embodiments, the cannula can include an anti-inflammatory agent,an anti-biotic agent, and/or an anti-clotting agent thereon.

Referring to FIG. 8, in some embodiments, the distal tip 888 of thecannula can include a molded or shaped form that promotes tissueinsertion. For example, as shown in FIG. 8, the distal tip can be coneshaped. The included angle formed by opposite sides of the cone can be,for example, an angle of greater than 10° and less than 40°. Further,the cone can have an axial lumen with dimensions that support a slip-fitinternal stylet.

In some embodiments, the reinforcing coil can have a fixed pitch fromthe proximal to the distal ends. In other embodiments, the reinforcingcoil can have a variable pitch from the proximal to distal end. Forexample, the pitch can vary from 1:1 to 1:n over a defined region and ata defined distance from either the distal or the proximal end. Thereinforcing coil can be made of stainless steel or of an engineeringpolymer. Further, the reinforcing coil can be a round wire or a flatwire. In some embodiments, the reinforcing coil can be injection molded.In some embodiments, the cannula can have a fixed durometer from theproximal to the distal end. In other embodiments, the cannula can have avaried durometer from the proximal to the distal end.

Although the depth control mechanism is described above with respect toan external insertion device, the depth control mechanism can also beused as part of an internal insertion mechanism, such as that describedwith respect to device 200.

In embodiments where a separate external insertion device (such asdevice 433) is used, the insertion device can be either reusable orsingle-use. For single use designs, the insertion device can include thecannula therein. In such an embodiment, a locking mechanism may be usedthat prevents the cannula from being released again.

In some embodiments, the fluid connections described herein can beattachable and detachable from the fluid source. The fluid connectioncan include, for example, a standard Luer lock or Minimed Paradigmconnection point for connection to the pump and/or fluid reservoir. Insome embodiments, the connection can include a valve, such as a septumvalve, that ensures that the connection remains in a closed state untilinitiation of an external fluid supply physical connection. Theconnection can be reusable, can have only one correct insertiondirection, can include features to prevent accidental disconnect, and/orcan allow for connection to commercially available infusion tube sets.In some embodiments, various lengths of pump tubing may be provided(e.g. 23, 32 and 43 inch long tubing) to accommodate patient comfort andconvenience.

In some embodiments, the devices described herein can have a visualindicator to show that the cannula has been fully inserted. For example,there can be a window in the hollow body to allow the user to see theindicator. The indicator can be, for example, a visual color change or avisual indicator symbol. Similarly, the devices described herein canhave a visual indicator to show that the cannula has been fullyretracted. This visual indicator can also be, for example, a window inthe hollow body and can include a color change or visual indicatorsymbol For example, referring to FIG. 3D, the cover 391 of the infusiondevice 300 can include an indicator 375 thereon that rotates as theouter disk 322 rotates. Further, the stationary housing 301 can includea ring 374 thereon with color-coded or other visual markers 355 a,b,c,d.As the outer disk 322 rotates (either to retract or insert the cannula),the indicator 375 can rotate to align with one or more of the markers355 a,b,c,d on the ring 374. For example, the first marker 355 a canindicate that the cannula is retracted, the second marker 355 b canindicate that the cannula is at 6 mm, the third marker 355 c canindicate that the cannula is at 8 mm, and the fourth marker 355 d canindicate that the cannula is at 10 mm. In FIG. 3D, the indicator 375 isat the fourth marker 355 d, indicating that the cannula is at 10 mm.

Advantageously, the infusion delivery device and system described hereincan be simple to use yet provide enhanced fluid delivery capabilities.For example, the system can allow for controlled delivery of fluid todifferent and precise depths, thereby permitting delivery to areas withboth thin and thick layers of fat or tissue. Further, the spiral orhelical insertion path of the cannula can advantageously help reducetissue trauma from insertion relative to devices that insert the cannulaat 90 degrees relative to the surface of the skin. Insertion along along spiral or helical path also helps prevent leakage of deliveredfluid, which can otherwise occur along short (e.g., 90 degree) insertionpaths. The described system can therefore reduce thrombus formation,inflammation, infiltration of the wound, and encapsulation.

Advantageously, the infusion delivery devices described herein can alsohave a small footprint, small packaging, and/or a small profile aboutthe skin while providing for an angled insertion path (i.e., non-90degree insertion). For example, the height of the device (i.e., distanceit extends about the skin) can be less than 0.5 inches, such as lessthan 0.4 inches or less than 0.3 inches. The device body can have adiameter of less than 1.5 inches, such as less than 1.2 inches, such asless than 1.0 inches. Further, the adhesive attachment patch can have adiameter of less than 1.5 inches, such as less than 1.4 inches.

Referring now to FIGS. 11-29B, another exemplary infusion system 400will be described. System 400 is similar in construction and method ofuse to the previously described systems. As shown in FIG. 11, all of theworking components of system 400 may be packaged within a generallycylindrical container having two cup-shaped halves that thread together.The lower portion of the container is referred to herein as jar 402 andthe upper portion as lid 404. FIG. 12 shows lid 404 unscrewed andremoved from jar 402, and inserter assembly 406 removed from within jar402 where it resides until use.

Referring to FIGS. 13 and 14, the other components of system 400, inaddition to inserter assembly 406 (not shown in FIGS. 13 and 14), thatare housed by jar 402 and lid 404 are shown. As with previouslydescribed embodiments, a tubing assembly 408 may be provided within thepackaging in a manner that encourages the user to fill the tubing withfluid, such as insulin, before inserting a transcutaneous cannula.Tubing assembly 408 includes a coiled length of tubing 410, a connectorassembly 412 located at one end of tubing 410, and a pump connector 414located at the opposite end of tubing 410. A tubing strip 416 may beprovided to help maintain tubing 410 coiled in a fashion that fitswithin lid 404. An adapter 418 may also be provided to receive pumpconnector 414 and secure it in lid 404, as will be subsequentlydescribed in more detail. This arrangement allows the user to easilyremove just the pump connector end of tubing 410 for connecting it to aninfusion pump reservoir for priming the tubing 410. Color dot 420, twofilter membranes 422, and a gasket 424 may also be installed in theunderside of lid 404 as will be subsequently described in more detail toaid the user in priming the tubing 410. In other embodiments, the tubingset may be located on top of the inserter assembly or elsewhere in thepackaging rather than in lid 404.

In this exemplary embodiment, a Tyvek label 426 is used during themanufacture of system 400 to cover aperture 427 in lid 404. Aperture 427is one of several apertures used to allow sterilization gas (such asEthylene Oxide) to freely circulate within the closed package duringproduct sterilization. After sterilization, label 426 is applied to lid404 to ensure infusion system 400 remains sterile. A larger label 428 isthen used to cover the top of lid 404.

Underneath removable inserter assembly 406 (not shown in FIGS. 13 and14), an anti-rotation pin 470 may be permanently attached to the bottomof jar 402 for mating with the bottom of inserter assembly 406, as willbe subsequently explained in more detail. A blank connector 472, similarto the main portion of connector assembly 412, may be releasablyattached to the bottom of jar 402 underneath inserter assembly 406.Blank connector 472 may be removed from jar 402 by the user to replaceconnector assembly 412 on the cannula base when not in use, as will besubsequently described in more detail. Another Tyvek label 426 is usedduring the manufacture of system 400 to cover aperture 474 in jar 402(used for circulation of sterilization gas, as described above), and alarger label 476 is used to cover the bottom of jar 402.

Referring to FIG. 15, the inside of jar 402 is shown. The bottom insidesurface of jar 402 may be provided with upwardly extending ribs 478configured to receive blank connector 472 (shown in FIGS. 13 and 14)when not in use. In some embodiments, ribs 478 extend 1 to 2 mm abovethe inside bottom of jar 402. Connector 472 may snap into place overribs 478 and may be released by pressing a release lever on connector472. The bottom of jar 402 may also be provided with upwardly extendingribs 480 to support the bottom of inserter assembly 406 (shown in FIG.12) above connector 472. In some embodiments, ribs 480 extend about 6 mmabove the inside bottom of jar 402. A portion of ribs 480 also serve asa boss to securely hold pin 470 in place. One or more inwardly extendingridges 482 (three are shown in FIG. 15) may be provided on the inside ofthe vertical walls of jar 402. Ridges 482 are configured to mate withrecesses 483 spaced around the lower periphery of inserter 406, as shownin FIGS. 17-19. These mating ridges 482 and recesses 483 serve to keepinserter 406 from rotating with respect to jar 402 when the inserter 406is being charged, as will be subsequently explained in more detail.

Referring to FIG. 16, the inside of lid 404 is shown. In a similarmanner to the bottom of jar 402 as previously described, the bottom oflid 404 (i.e. the underside of the top surface) may be provided withdownwardly extending ribs 478 configured to receive connector assembly412 (shown in FIGS. 13 and 14) before use. In some embodiments, ribs 478extend 1 to 2 mm below the inside bottom surface of lid 404. Connectorassembly 412 may snap into place over ribs 478 and may be released bypressing a release lever on connector assembly 412. A portion of ribs478 (shown with reference numerals 484) may be configured to hold colordot 420, two filter membranes 422, and gasket 424 (shown in FIGS. 13 and14.) Ribs 484 hold these four circular items directly below the needleof connector assembly 412 such that when lid 404 is inverted (e.g.resting on a horizontal surface like a cup) and tubing assembly 408 isbeing primed, liquid drips from the needle onto the filter membranes 422and travels down through them into color dot 420 to change its color andindicate to the user that the tubing has been primed. Alternatively,color dot 420 may start as a brightly colored piece of PVC laminatingfilm that is not readily visible through filter membranes 422 until themembranes become wet. The bottom of lid 404 may also be provided withdownwardly extending ribs 486 configured to receive adapter 418 (shownin FIGS. 13 and 14) such that pump connector 414 may be removably heldin lid 404 until ready for use. In some embodiments, ribs 486 extendabout 8 and 11 mm below the inside bottom of lid 404.

Referring to FIGS. 17-23, various views of the inserter assembly 406 areshown. As best seen in FIGS. 17-19, inserter assembly 406 is providedwith a bottom housing 488, and a top housing 490 that can rotate in alimited manner about a vertical axis with respect to bottom housing 488to charge/wind the inserter. An adhesive patch 492 is provided on thebottom surface of bottom housing 488 for first attaching the entireinserter assembly 406 to an insertion site of a user's skin while aninfusion cannula is inserted, and then for retaining a portion ofinserter assembly 406 on the insertion site. Release buttons 494 areprovided on opposite sides of top housing 490 for triggering the cannulainsertion sequence after the inserter assembly 406 has beencharged/wound and attached to the user's skin.

Referring to FIGS. 20-23, other components of inserter assembly 406include middle fork 496, torsion spring 498, bottom rotor 500, top rotor502, bottom fork 504, stylet 506, cannula 508, rotor 510, septum 512,base 514. M2×20 mm hex screw 516, M2 stainless steel washer 518, M2 PTFEwasher 520, M2 locknut 522 and label 524. Bottom fork 504 is providedwith a hexagonal recess in the center of its bottom surface forreceiving locknut 522. Screw 516 and locknut 522 captivate top housing490, middle fork 496, bottom housing 488, bottom rotor 500, top rotor502 and bottom fork 504 therebetween, and each component is permitted torotate in a limited manner with respect to the other components. Torsionspring 498 is engaged between the bottom of middle fork 496 and the topof bottom rotor 500, initially in a relaxed state. When the inserterassembly 406 is charged, this single spring 498 is wound up and urgesmiddle fork 496 in a clockwise direction (when viewed from above)relative to stationary bottom housing 488, and urges bottom rotor 500 ina counter-clockwise direction.

When inserter assembly 406 is assembled, base 514 is adhered to the topside of adhesive patch 492. Rotor 510 is rotatably retained on thecenter hub of base 514. Septum 512 is located in a curvedcircumferential channel through a radially extending wing of rotor 510.Cannula 508 is located on stylet 506 such that a short tip portion ofstylet 506 extends from the distal end of cannula 508 and a proximalportion of stylet 506 including a 90 degree bend extends from theproximal end of cannula 508. The distal end of stylet 506 and cannula508 extend from the curved circumferential channel in a clockwisedirection (when viewed from above). The proximal end of cannula 508terminates inside the curved channel in a sealed manner with thechannel, while the proximal end of stylet continues through the channeland septum 512, and extends out the opposite end of the channel in thecounter-clockwise direction.

Throughout the insertion process and later use of the infusion set, theadhesive patch 492, base 514, rotor 510, septum 512 and cannula 508remain together as a unit referred to as the base assembly 526. Baseassembly 526 is first releasably attached to the rest of inserterassembly 406 by way of bottom rotor 500. Once the distal end of cannula508 is inserted through a user's skin and stylet 506 is retracted, baseassembly 526 is released from inserter assembly 406 and becomes aseparate unit that remains on the user's skin.

Inserter assembly 406 may be provided to a user in a sterilized andsealed state inside closed jar 402 and lid 404 (as shown by FIGS. 11 and12), such as with a plastic seal (not shown) that can cover the junctionbetween jar 402 and lid 404. In some embodiments, a plastic seal is notneeded since an airtight seal may be formed when jar 402 and lid 404 arescrewed together. but a tamper resistant label may be applied toindicate that the packaging remains unopened. In any of these shippingor storage states, torsion spring 498 is provided in a relaxed state.This prevents the plastic parts of inserter assembly 406 from sitting ina stressed state for a long period of time, which could result in theparts changing shape and not functioning consistently or reliably.According to aspects of the present disclosure, torsion spring 498 isautomatically charged/wound as the packaging for inserter assembly 406is opened. After any plastic seal is removed from around jar 402 and lid404, lid 404 is unscrewed from jar 402. The rotation of unscrewing lid404 simultaneously charges spring 498 by rotating top housing 490counter-clockwise (as viewed from above) relative to bottom housing 488.As previously indicated, bottom housing 488 and jar 402 are providedwith mating features that rotationally lock the two components together.The inside of vertical sidewalls of lid 404 may be provided with a pairof ratchet tabs 528 (shown in FIGS. 14 and 16) configured to engage withopposing ratchet tabs located on release buttons 494 when lid 404 isrotated in a counter-clockwise direction, so that top housing 490 isturned counter-clockwise as lid 404 is unscrewed from jar 402. In thisstate, middle fork 496 is rotationally locked to top housing 490 so thatit also rotates with top housing 490 and lid 404. Also, anti-rotationpin 470 (shown in FIGS. 13 and 14) extends from jar 402 up into thebottom of inserter assembly 406 to prevent base 514, bottom fork 504 andbottom rotor 500 from rotating during charging. Therefore, whencontainer lid 404 is unscrewed, top housing 490 and middle fork 496 arethe only components that rotate with it, along with the top portion oftorsion spring 498. Top housing 490 and middle fork 496 both rotateabout 360 degrees counter-clockwise before they each lock into place andinserter assembly 406 is fully charged. Top housing 490 will not rotateagain during the cannula/stylet insertion and stylet retraction process,but middle fork 496 will rotate back about 120 degrees in the clockwisedirection, as will be further described below. Once lid 404 is unscrewedfrom jar 402 (as shown in FIG. 12), the automatically charged inserterassembly 406 may be removed from jar 402.

As previously described, once lid 404 is unscrewed from jar 402, pumpconnector 414 located at one end of tubing 410 (shown in FIG. 13) may beremoved from lid 404, connected to an infusion pump, and tubing 410 maybe primed with fluid from the pump reservoir. After the charged inserterassembly 406 is removed from jar 402, the lining of adhesive patch 492(shown in FIG. 18) may be removed to expose the adhesive. The bottom ofinserter assembly 406 may then be applied to an insertion site on theskin of the user and held in place with adhesive patch 492.

Still referring to FIGS. 20-23, once the charged insertion assembly 406has been applied to the skin of a patient, it may be activated toautomatically insert the enclosed cannula under the skin. In thisexemplary embodiment, both release buttons 494 are pushed inwardly toactivate the firing sequence. The release buttons 494 rotationallyunlock middle fork 496 from top housing 490, allowing torsion spring 498to drive middle fork 496 about 120 degrees in the clockwise direction.Middle fork 496 is provided with radially protruding features on acentral hub (best seen in FIG. 21) that allow it to simultaneously drivebottom fork 504 about 120 degrees in the clockwise direction. Bottomfork 504 in turn drives rotor 510 clockwise, causing stylet 506 andcannula 508 to be driven into the user's skin in a helical fashion, aswill be subsequently described in more detail. Both middle fork 496 andbottom fork 504 stop rotating and are locked in place.

When bottom fork 504 reaches the end of its clockwise travel (markingthe end of the stylet and cannula insertion cycle), tabs on the top ofmiddle fork 496 force arms in bottom housing 488 to disengage bottomrotor 500 from its locked position, initiating the start of the styletretraction cycle. At this point, the top of torsion spring 498 has beenwound about 360 degrees in counter-clockwise direction by the chargingcycle and unwound about 120 degree in the clockwise direction by thestylet and cannula insertion cycle. This leaves enough stored energy inspring 498 to drive the bottom rotor 500 about 240 degrees in thecounter-clockwise direction during the stylet retraction cycle. Bottomrotor 500 drives top rotor 502 which in turn drives stylet 506 about 240degrees in the counter-clockwise direction, which removes stylet 506from cannula 508 and withdraws stylet 506 out of sight into theinserter, as will be subsequently described in more detail. Once bottomrotor 500 reaches the end of its counter-clockwise travel, lockingfeatures on bottom rotor 500 release base 514 so that inserter assembly406 can be removed from the user, leaving adhesive patch 492, base 514,rotor 510 and cannula 508 intact on the user.

As disclosed above, once release buttons 494 are pressed, theaforementioned components cooperate to automatically insert cannula 508and stylet 506 through the skin in a clockwise direction, then retractstylet 506 in a counter-clockwise direction, and then release the baseassembly from the inserter assembly without further interaction from theuser. A single spring 498 provides all of the energy required for thisautomatic insertion and retraction process. Before, during and afterthis process, the user is never able to see or touch stylet 506 orcannula 508, providing further safety and comfort to the user. In otherembodiments, only one release button 494 may be provided, or if multiplerelease buttons are provided only one needs to be pressed toautomatically activate the insertion, retraction and release cycles.This may be referred to as a single “trigger event”, regardless of howmany buttons need to be pushed.

Referring to FIGS. 24A-24P, the steps of applying base 514 to a user,automatically inserting cannula 508, and connecting the primed infusionpump tubing to base 514 are shown. The steps shown in FIGS. 24A-24Dcorrespond to some of the steps described above in reference to FIGS.20-23, but focus on what is occurring with the components in baseassembly 526 rather than the components in the rest of inserter assembly406. FIG. 24A shows base assembly 526 in a ready to deploy state, wheninserter assembly 406 is first applied to the user's skin. The rest ofinserter assembly 406 (shown in FIGS. 20-23) is still attached to baseassembly 526 at this point but is removed from FIGS. 24A-24D forclarity. As previously indicated, base assembly 526 includes adhesivepatch 492, base 514, rotor 510, septum 512 and cannula or catheter 508.

Referring to FIG. 24A, when the inserter is in the ready to deploy stateas shown, cannula 508 is mounted over stylet 506, with the pointeddistal tip (not shown) of stylet 506 protruding slightly from the distalend of cannula 508. The proximal end of cannula 508 terminates insidethe circumferential channel of rotor 510, while the proximal bent end ofstylet 506 extends through septum 512 (not shown) and out through theopposite end of the channel. At this stage, the distal ends of stylet506 and cannula 508 are retracted within base 514 rather than extendingthrough adhesive patch 492.

Referring to FIG. 24B, base assembly 526 is shown with the distal ends(not shown) of stylet 506 and cannula 508 deployed downwardly into theskin (not shown but located beneath adhesive patch 492.) Comparing FIG.24B with FIG. 24A, it can be seen that rotor 510, catheter 508 andstylet 506 have been rotated together about 120 degrees in the clockwisedirection, as previously described in reference to FIGS. 20-23. Stylet506 and cannula 508 follow a generally helical path through and beneaththe skin due to the stylet 506 and/or the cannula 508 having beenpre-formed in a helical shape and due to the downwardly sloped camsurface 530 of base 514 that guides stylet 506 and cannula 508 down intothe skin. In this exemplary embodiment, stylet 506 and cam surface 530each have a 30 degree angle relative to the surface of the skin, andstylet 506 has a constant nominal radius of 7.15 mm.

Referring to FIG. 24C, base assembly 526 is shown with stylet 506rotated back alone and retracted from cannula 508 and from the channelin rotor 510. As previously described in reference to FIGS. 20-23,stylet 506 is retracted about 240 degrees in the counter-clockwisedirection.

Referring to FIG. 24D, base assembly 526 is shown with stylet 506removed completely, as occurs when base 514 is released from the rest ofinserter assembly 406 and the inserter is removed with stylet 506retracted within it.

Referring to FIGS. 24E and 24F, an exploded top view and exploded bottomview, respectively, show details of connector assembly 412 before it ismated with base assembly 526. As shown in FIG. 24E, tubing 410 entersradially into a groove 532 that extends around the periphery of the topsurface of connector assembly 412. Groove 532 and tubing 410 extendabout 270 degrees around connector assembly 412 before tubing 410 passesinto the interior of connector assembly 412. As shown in FIG. 24F, whenthe tubing passes into the interior of connector assembly 412, itconnects with needle 534 which continues to extend tangentially into theinterior of connector assembly 412.

Referring to FIG. 24G, a cross-section view shows connector assembly 412placed onto base assembly 526 in an unlocked position. This view moreclearly shows tubing 410 extending along periphery groove 532, and anenlarged portion formed on the distal end of tubing 410 for receivingthe proximal end of needle 534. As shown, connector assembly 412includes an internal boss configured to hold a middle portion of needle534 in a controlled orientation such that the distal end of needle 534can pass through septum 512 when the connector assembly 412 is rotatedclockwise with respect to base assembly 526.

Referring to FIG. 24H, a cross-section view similar to FIG. 24G isshown, but with connector assembly 412 rotated from the unlockedposition to the locked position. To move to the locked position,connector assembly 412 is rotated 90 degrees clockwise relative to baseassembly 526. As connector assembly 412 is rotated, the distal end ofneedle 534 pierces septum 512 to enter the channel of rotor 510, suchthat it is in fluid communication with the proximal end of cannula 508as shown. Locking arm 536 prevents connector assembly 412 from rotatingback to the unlocked position until it is pressed radially inward.

Referring to FIG. 24I, a bottom view of FIG. 24G shows connectorassembly 412 coupled with base assembly 526 in an unlocked position(with adhesive patch 492 removed for clarity.) A center post whichdepends from the bottom of connector 412 can be seen protruding throughan aperture in the center of base 514. Radially extending tabs 538 and540 may be provided on this center post of base 514, which pass throughmating apertures in base 514 when connector 412 is aligned with it inthe unlocked position. As connector 412 is rotated towards the lockedposition (counter-clockwise as viewed from below in FIG. 24I), tabs 538and 540 travel along ramps 542 to retain connector 412 on base 514.

Referring to FIG. 24J, a top view similar to FIG. 24G but not incross-section shows connector assembly 412 placed onto base assembly 526in an unlocked position.

Referring to FIG. 24K, a top view similar to FIG. 24H but not incross-section shows connector assembly 412 rotated 90 degrees clockwisewith respect to base assembly 526 into a locked position.

Referring to FIG. 24L, a top view similar to FIG. 24K is shown. Thisfigure illustrates that peripheral groove 532 of connector assembly 412may be provided with multiple tubing exit points. In this exemplaryembodiment, three tubing exit points 544, 546 and 548 are provided. Inother embodiments, a greater or lesser number of tubing exit points maybe provided. The user may choose to leave tubing 410 in exit point 544,as shown in FIG. 24K. If instead the user prefers that tubing 410extends in a different direction from connector 412 toward the infusionpump (not shown), the user may lift a portion of tubing 410 out ofperipheral groove 532 and lock the tubing into exit point 546, or lockthe tubing into exit point 548 as shown. In embodiments with or withoutthese multiple tubing exit points, an indicator may be provided oninserter assembly 406, such as the arrow shown on top of inserterassembly 406 in FIG. 17, to indicate to the user before applying theinserter assembly to the skin which direction the tubing will be exitingthe base assembly 526.

In the state shown in FIG. 24K or 24L, the infusion set is ready to useand the infusion pump may be activated.

Referring to FIG. 24M, a top view similar to FIG. 24L is shown. In thisview, release arm 536 has been pressed inwardly and connector assembly412 has been rotated 90 degrees counter-clockwise relative to baseassembly 526 into the unlocked position. In this position, tubing 410 isremoved from fluid communication with cannula 508 (not shown but stillinserted under the user's skin), and connector assembly 412 may beremoved from base 514.

Referring to FIG. 24N, this top view shows base assembly 526 remainingon the user's skin after connector assembly 412 has been unlocked andremoved.

Referring to FIG. 24O, this top view shows blank connector 472 placedonto base assembly 526 in an unlocked position. A user may wish totemporarily replace connector assembly 412 with blank connector 472 toprotect base assembly 526 when not in use, such as when the infusionpump and tubing is removed for showering. As previously described inreference to FIGS. 13-15, blank connector 472 may be stored in jar 402until needed.

Referring to FIG. 24P, a top view similar to FIG. 24O. This view showsblank connector 472 after it has been rotated 90 degrees clockwiserelative to base assembly 526 into the locked position. To remove blankconnector 472, release arm 536 is pressed in and blank connector isrotated 90 degree counter-clockwise. When the user is ready to removebase assembly 526 completely, adhesive patch 492 is peeled back from theuser's skin and pulled off, taking the cannula and other components withit.

In some embodiments, inserter assembly 406 has a maximum diameter nogreater than 2.25 inches and a height no greater than 1.5 inches. Insome embodiments, when connector assembly 412 is coupled to base 514,the combined assembly has a maximum diameter no greater than 1.25 inchesand a height above the user's skin no greater than 0.3 inches.

Referring to FIGS. 25A-25C, various views are provided showing detailsof exemplary cannula 508 constructed according to aspects of thedisclosure. Applicants have found that the unique combination ofspecific cannula and stylet features disclosed herein provide a soft,kink-resistant cannula for increased user comfort, and one that isreliably self-inserted (i.e. inserted without a needle over the cannula)without collapsing, buckling or crushing. While this cannula and styletdesign is described in relation to helical inserter infusion system 400disclosed above, it should be noted that it may also find usefulapplication in non-helical self-insertion infusion systems, and may beintroduced through the skin at any angle from 90 degrees to close to 0degrees.

In the exemplary embodiment disclosed herein, cannula 508 is formed froma polyether block amide (PEBA) thermoplastic elastomer, such as a PEBAsold under the tradename of Pebax® by Arkema Inc. headquartered in Kingof Prussia, Pa. Applicants have found that using a Pebax® materialhaving a durometer of 72D, in combination with other features disclosedherein, provides greatly improved cannula performance over lowerdurometers such as 63D. In this embodiment, cannula 508 has a length Lof 24.8 mm and an outside diameter of 0.56 mm. Except for a short regionat the distal tip of cannula 508 (as shown in FIG. 25C), the insidediameter of the cannula is 0.41 mm. A section extending proximally 0.71mm from the distal tip of cannula 508 has an inside diameter of 0.26 mm,and a conical taper having an included angle of 20 degrees, as shown inFIG. 25C, A radius of 0.03 mm may be applied to the leading distal edgeof the taper. Thus, cannula 508 is open at both ends with a single axiallumen extending between the openings. In other embodiments, the nominalconical taper angle may be between about 10 and about 30 degrees.

In this exemplary embodiment, three holes 550 are formed in cannula 508,each through one wall of the Pebax® only and having a diameter of 0.15mm. Holes 550 may be placed 2 mm apart from each other and no more than2 mm from the distal tip of cannula 508. The three holes 550 may beplaced evenly around the circumference of cannula 508 such that they are120 degrees apart. With this axial and circumferential spacing, holes550 form a helical pattern. In other embodiments (not shown), fewer,more or no holes may be provided, they may have a different diameter ordiameters, and various alternative spacing patterns may be used.

As depicted in FIGS. 25A and 25C, a helical coil 552 may be placedinside the central lumen of cannula 508 such that it extends from theproximal end of the cannula up to within 0.71 mm from the distal tipwhere the cannula has a reduced inside diameter. In this exemplaryembodiment, coil 552 is formed from stainless steel 304 wire, and thewire has a diameter of 0.05 mm. Coil 552 is formed to have an outsidediameter of 0.41 mm to match the inside diameter of cannula 508, and hasan inside diameter of 0.30 mm to match the outside diameter of stylet506 (shown in FIG. 26.) As shown in FIG. 25A, the length of coil 552 maybe divided into two regions A and B, with region A having an axiallength of 14 mm (not drawn to scale.) In region A, coil 552 is providedwith a pitch of 0.075 mm such that there is a gap of 0.025 mm betweenadjacent turns of the coil. In region B, coil 552 is provided with aclosed pitch equal to the wire diameter (0.05 mm) such that there are nogaps between adjacent turns of the coil. This arrangement allows cannula508 to have sufficient strength for insertion while remaining highlyflexible for user comfort. The open pitch in region A also permitsincreased fluid flow from the central lumen of cannula 508 laterallyoutward through holes 550. In other embodiments, the gap betweenadjacent turns of the coil in distal region A is between about 25% andabout 100% of the coil wire diameter. In this exemplary embodiment, coil552 is wound in a right-hand direction (although shown in the figures asif it were wound in a left-hand direction.)

Referring to FIG. 25B, the length of cannula 508 may he divided intoregions C and D, with region D having an axial length of 5 mm (not drawnto scale relative to regions A and B in FIG. 25A or other dimensions.)In this exemplary embodiment, only region C is siliconized to reduce theforce needed to insert cannula 508 through the skin of the user. RegionD remains inside the base assembly and should not be siliconized. RegionC may be siliconized with a silicon dispersion such as MED-4162 sold byNuSil Technology LLC in Carpinteria, Calif. The silicon may be dilutedby mixing one part MED-4162 with four parts xylene. After the mixture isapplied, it may be heat cured at 260 degrees F.

Referring to FIGS. 26A and 26B, details of stylet 506 are shown. In thisexemplary embodiment, stylet 506 is formed from full hard stainlesssteel 304 wire having a wire diameter of 0.030 mm. Stylet 506 has anoverall axial length of 37.40 mm when in a straight state. The majorityof stylet 506 is formed into a curve having an inside diameter of 14.29mm, as shown in FIG. 26A. A straight portion 4.26 mm long is left at theproximal end 554, and a straight portion 2.00 mm long is left at thedistal end 556. As shown in FIG. 26B, a 35 degree bevel is provided onthe proximal end 554 of stylet 506, and a 15 degree trocar tip isprovided on the distal end 556. The trocar tip has three beveled facesrotated 120 degrees apart from one another around the circumference ofthe distal tip, with each face having a 15 degree angle and extendingproximally 0.57 mm from the distal tip. In other embodiments, the angleof the trocar faces may be larger or smaller than 15 degrees, but itshould be less than the desired insertion angle relative to the skin toallow the tip to penetrate the skin. In this exemplary embodiment, thedesired insertion angle is 30 degrees.

Referring to FIG. 26C, cannula 508 is shown assembled over stylet 506.In use, the distal end 556 of stylet 506 protrudes from the distal endof cannula 508 a distance of 0.25 mm (measured from the unsharpenedportion rather than the sharp tip), as shown. The proximal end 554 ofstylet 506 extends from the proximal end of cannula 508 a distance of11.75 mm from the beveled tip, as shown.

Referring to FIGS. 27A and 27B, graphs showing lateral stiffness testresults for cannula 508 and stylet 506 are provided. The graphs comparethe test results for cannula 508 and stylet 506 to a previous designversion developed by the present applicants, and to commerciallyavailable prior art insulin infusion cannulas made of Teflon™. Duringthe testing, the cannulas were held 10 mm from their distal tips while atest force was applied laterally at 5 mm from the tip. The lateralforces, measured in Newtons, required to deflect the distal tip 2 mm and4 mm were recorded. FIG. 27A shows the test results for the cannulasonly, while FIG. 27B shows the test results when stylets were presentinside the cannulas. (The prior art cannulas were not tested withstylets.)

Referring to FIGS. 28A and 28B, graphs showing axial insertion forcesfor cannula 508 and stylet 506 are provided. The graphs compare the testresults for cannula 508 and stylet 506 to the previous design versiondeveloped by the present applicants, and to commercially available priorart insulin infusion cannulas made of Teflon™. For FIG. 28A, the testswere conducted at a 90 degree insertion angle (i.e. the stylet andcannula were inserted perpendicular to the skin). For FIG. 28B, thetests were conducted at a 30 degree insertion angle (i.e. the stylet andcannula were inserted 30 degrees above being parallel to the skin).

In order to achieve the favorable results shown in FIGS. 27A-28B for thefinal iterations of cannula 508 and stylet 506, many countervailingparameters needed to be added or changed relative to the prior art andfirst iteration designs.

Referring to FIGS. 29A and 29B, trigonometric parameters for the helicalinsertion of cannula 508 are provided. FIG. 29A depicts cannula 508extending in a helical fashion from the bottom of base 514. A sweepangle 558 as shown is formed between the distal tip of cannula 508 andthe point where it passes through the outer surface of the skin. FIG.29B shows the trigonometric relationship between the angle that cannula508 makes with the surface of the skin, the cannula length under theskin, the depth of the distal tip of the cannula beneath the skin, andthe two-dimensional arc length that the cannula projects onto thesurface of the skin.

In some embodiments, it is desirable to insert cannula 508 into the skinsuch that its distal tip resides between 4 and 9 mm below the surface(measured perpendicularly from the surface of the skin.) Because of theslenderness and softness of cannula 508 and stylet 506, and the varyingdensities of tissue anatomies below the skin, the cannula and stylet arenot likely to travel in a perfectly helical path. The exemplary infusionsystem 400 disclosed herein is designed to insert a 14 mm length ofcannula 508 at an angle of 30 degrees below the skin with a nominalhelical radius of 7.15 mm such that the distal tip resides 7 mm belowthe surface, as shown in the middle line of the table in FIG. 29B. Theother two lines of the table show the calculated insertion angles andother parameters that may occur when the distal tip instead goes either4 or 9 mm deep. While the disclosed system 400 is designed to insert thecannula in a nominally helical path, it should be noted that the actualpath that the cannula takes may vary. In other embodiments, thedisclosed design may be modified (without necessarily departing from thescope of the claims) such that the nominal intended cannula path ispartially or entirely spiral (i.e. changing in radius), curved (in twoand or three dimensions), helical, straight, have other geometrictrajectories, or combinations of the foregoing.

The systems described herein can advantageously allow transcutaneousplacement of a soft cannula safely and automatically. The systemsadvantageously also do not require the disposal of a sharp, contaminatedneedle, since the stylet can be fully retracted back into the housing.The systems described herein are designed to be single use disposableunits, but in other embodiments portions of the system such as theinserter may be made to be multi-use.

The disclosed infusion devices can be used, for example, for insulindelivery and thus may help to reduce the burden of managing diabetes by:(1) extending the wear duration from three to seven or more days,matching insulin pump cartridge and CGM sensor lifetime, (2) preservinginfusion sites by minimizing tissue trauma, scar formation andlipodystrophy, (3) reducing the frequency of set failure and unexpectedhyperglycemia. (4) providing more predictable insulin response byenhancing absorption, and/or (5) improving blood glucose control with alower incidence of hypoglycemia.

When a feature or element is herein referred to as being “on” anotherfeature or element, it can be directly on the other feature or elementor intervening features and/or elements may also be present. Incontrast, when a feature or element is referred to as being “directlyon” another feature or element, there are no intervening features orelements present. It will also be understood that, when a feature orelement is referred to as being “connected”, “attached” or “coupled” toanother feature or element, it can be directly connected, attached orcoupled to the other feature or element or intervening features orelements may be present. In contrast, when a feature or element isreferred to as being “directly connected”. “directly attached” or“directly coupled” to another feature or element, there are nointervening features or elements present. Although described or shownwith respect to one embodiment, the features and elements so describedor shown can apply to other embodiments. It will also be appreciated bythose of skill in the art that references to a structure or feature thatis disposed “adjacent” another feature may have portions that overlap orunderlie the adjacent feature.

Terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.For example, as used herein, the singular forms “a”. “an” and “the” areintended to include the plural forms as welL unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, steps, operations, elements, components, and/orgroups thereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if a device in theFIGS. is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures. Thus, the exemplary term “under” can encompass both anorientation of over and under. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Similarly, the terms“upwardly”, “downwardly”, “vertical”, “horizontal” and the like are usedherein for the purpose of explanation only unless specifically indicatedotherwise.

Although the terms “first” and “second” may be used herein to describevarious features/elements (including steps), these features/elementsshould not be limited by these terms, unless the context indicatesotherwise. These terms may be used to distinguish one feature/elementfrom another feature/element. Thus, a first feature/element discussedbelow could be termed a second feature/element, and similarly, a secondfeature/element discussed below could be termed a first feature/elementwithout departing from the teachings of the present disclosure.

Throughout this specification and the claims which follow, unless thecontext requires otherwise, the word “comprise”, and variations such as“comprises” and “comprising” means various components can be co-jointlyemployed in the methods and articles (e.g., compositions and apparatusesincluding device and methods). For example, the term “comprising” willbe understood to imply the inclusion of any stated elements or steps butnot the exclusion of any other elements or steps.

In general any of the apparatuses and methods described herein should beunderstood to be inclusive, but all or a sub-set of the componentsand/or steps may alternatively be exclusive, and may be expressed as“consisting of” or alternatively “consisting essentially of” the variouscomponents, steps, sub-components or sub-steps.

As used herein in the specification and claims, including as used in theexamples and unless otherwise expressly specified, all numbers may beread as if prefaced by the word “about” or “approximately.” even if theterm does not expressly appear. The phrase “about” or “approximately”may be used when describing magnitude and/or position to indicate thatthe value and/or position described is within a reasonable expectedrange of values and/or positions. For example, a numeric value may havea value that is +/−0.1% of the stated value (or range of values), +/−1%of the stated value (or range of values), +/−2% of the stated value (orrange of values), +/−5% of the stated value (or range of values), +/−10%of the stated value (or range of values), etc. Any numerical valuesgiven herein should also be understood to include about or approximatelythat value, unless the context indicates otherwise. For example, if thevalue “10” is disclosed, then “about 10” is also disclosed. Anynumerical range recited herein is intended to include all sub-rangessubsumed therein. It is also understood that when a value is disclosedthat “less than or equal to” the value. “greater than or equal to thevalue” and possible ranges between values are also disclosed, asappropriately understood by the skilled artisan. For example, if thevalue “X” is disclosed the “less than or equal to X” as well as “greaterthan or equal to X” (e.g., where X is a numerical value) is alsodisclosed. It is also understood that the throughout the application,data is provided in a number of different formats, and that this data,represents endpoints and starting points, and ranges for any combinationof the data points. For example, if a particular data point “10” and aparticular data point “15” are disclosed, it is understood that greaterthan, greater than or equal to, less than, less than or equal to, andequal to 10 and 15 are considered disclosed as well as between 10 and15. It is also understood that each unit between two particular unitsare also disclosed. For example, if 10 and 15 are disclosed, then 11,12, 13, and 14 are also disclosed.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the disclosure as described by the claims. Forexample, the order in which various described method steps are performedmay often be changed in alternative embodiments, and in otheralternative embodiments one or more method steps may be skippedaltogether. Optional features of various device and system embodimentsmay be included in some embodiments and not in others. Therefore, theforegoing description is provided primarily for exemplary purposes andshould not be interpreted to limit the scope of the disclosure as it isset forth in the claims.

The examples and illustrations included herein show, by way ofillustration and not of limitation, specific embodiments in which thesubject matter may be practiced. As mentioned, other embodiments may beutilized and derived there from, such that structural and logicalsubstitutions and changes may be made without departing from the scopeof this disclosure. Such embodiments of the inventive subject matter maybe referred to herein individually or collectively by the term“invention” or “disclosure” merely for convenience and without intendingto voluntarily limit the scope of this application to any singleinvention or inventive concept, if more than one is, in fact, disclosed.Thus, although specific embodiments have been illustrated and describedherein, any arrangement calculated to achieve the same purpose may besubstituted for the specific embodiments shown. This disclosure isintended to cover any and all adaptations or variations of variousembodiments. Combinations of the above embodiments, and otherembodiments not specifically described herein, will be apparent to thoseof skill in the art upon reviewing the above description.

What is claimed is:
 1. A system for delivering fluid to a usertranscutaneously, the system comprising: a base assembly configured tobe located on the user's skin; a flexible subcutaneous infusion cannulaconfigured to be positioned fully within the base assembly prior toinsertion; an inserter assembly coupled to the base assembly, theinserter assembly being configured to drive the wound flexiblesubcutaneous infusion cannula from the base assembly through the user'sskin at an angle of less than 45°; and a fluid connection assemblyconfigured to fluidically connect the base assembly to a source ofdelivery fluid.
 2. The system of claim 1, wherein the inserter assemblyis removably coupled to the base assembly.
 3. The system of claim 1,further comprising a sharp inner stylet configured to extend through theflexible subcutaneous infusion cannula.
 4. The system of claim 3,wherein the sharp inner stylet has a pre-set shape.
 5. The system ofclaim 1, wherein the base assembly includes an adhesive on at least onesurface thereof configured to attach the base assembly to the user'sskin.
 7. The system of claim 1, wherein the flexible subcutaneousinfusion cannula includes an outer tube and an inner reinforcement coil.8. The system of claim 1, wherein the flexible subcutaneous infusioncannula includes two or more fluid exit holes at or near the distal endthereof.
 9. The system of claim 3, wherein the inserter assemblyincludes an automatic retraction mechanism configured to move the sharpinner stylet from an advanced position to a retracted position aftercompletion of a cannula insertion cycle.
 10. The system of claim 9,wherein the inserter assembly includes an automatic release mechanismconfigured to decouple the inserter assembly from the base assemblyafter completion of a stylet retraction cycle.
 11. The system of claim10, wherein the inserter assembly is configured to automatically performthe cannula insertion cycle, the stylet retraction cycle and a releasecycle in succession after a single trigger event without furtherinteraction from the user.
 12. The system of claim 11, wherein theinserter assembly includes a single drive spring configured to supplyall energy required to drive the cannula insertion cycle, the styletretraction cycle and the release cycle.
 13. The system of claim 1,wherein the fluid connection assembly includes tubing and an element orassembly that changes color when the tubing has been primed with fluid.14. The system of claim 1, wherein the fluid connection assemblyincludes a releasable fluid interconnect assembly configured toreleasably connect the base assembly to the source of delivery fluid,and wherein the source of delivery fluid is external to the baseassembly.
 15. The system of claim 15, wherein the releasable fluidinterconnect assembly includes a needle and a septum, wherein the fluidinterconnect assembly is configured to insert an end of the needlethrough the septum after a cannula stylet is withdrawn from the septum.16. A system for delivering fluid to a user transcutaneously, the systemcomprising: a base assembly configured to be located on the user's skin,the cannula base assembly including a subcutaneous infusion cannulahaving a central lumen therethrough, wherein the subcutaneous infusioncannula includes a reinforcing coil extending along a portion of thecentral lumen; an inserter assembly coupled to the base assembly, theinserter assembly including a sharp stylet configured to pass throughthe central lumen of the subcutaneous infusion cannula, the inserterassembly being configured to drive the sharp stylet and subcutaneousinfusion cannula together through the user's skin at an angle of lessthan 45 degrees without a needle placed over the subcutaneous infusioncannula; and a fluid connection assembly configured to fluidicallyconnect the base assembly to a source of delivery fluid.
 17. The systemof claim 16, wherein the reinforcing coil has a first section with afirst coil pitch and a second section with a second coil pitch, thefirst section being located more distally in the cannula than the secondsection, wherein the first coil pitch is greater than the second coilpitch.
 18. The system of claim 17, wherein the first coil pitch is anopen pitch and the second coil pitch is a closed pitch.
 19. The systemof claim 18, wherein the first section includes a plurality of holesthrough a side wall of the subcutaneous infusion cannula.